1. Field of the Invention
The present invention relates to a display device and a manufacturing method of a display device.
2. Description of the Related Art
Currently popular display devices include a liquid crystal display (LCD), a plasma display device (PDP), an organic light emitting display (OLED), a field effect display (FED), and an electrophoretic display (EPD).
Particularly, the organic light emitting diode (OLED) display includes a plurality of OLEDs formed of a hole injection electrode, an organic emission layer, and an electron injection electrode. Each organic light emitting diode emits light when excitons, which are generated as electrons and holes are combined, drop from an excited state to a ground state and emit photons of light corresponding to the energy difference between the two energy states, and the OLED display displays an image using the light. The organic light emitting device can be used for a lighting device and as a display device for displaying predetermined images.
The organic light emitting element may be deteriorated by external factors such as external moisture, oxygen, or ultraviolet rays (UV), so packaging methods for encapsulating the organic light emitting element are important, and the organic light emitting diode (OLED) display is required to be manufactured to be either thin or flexible for various types of applications.
In order to encapsulate the organic light emitting element and form a thin organic light emitting diode (OLED) display that is bendable, a thin film encapsulation (TFE) method has been developed. In the thin film encapsulation method, a display area is covered with a thin film encapsulation layer by alternately stacking an inorganic layer and an organic layer over the organic light emitting elements that are formed in the display area of the display substrate. When the display substrate of the organic light emitting diode (OLED) display including the thin film encapsulation layer is formed with a flexible film, it can be easily bent, and making it slim has practical advantages.
Meanwhile, a protection film protecting a display substrate may be attached under the display substrate, and an FPCB (flexible printed circuit board) transmitting a driving signal may be attached under the protection film.
However, if the organic light emitting diode (OLED) display to which a power source is turned off is exposed to strong natural light (for example sunlight), a lower portion of the display substrate is entirely exposed to view such that an adhesion state of the FPCB with the display panel (for example, wrinkled the FPCB) is revealed.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.